Rotational speed governor with a pair of resilient flexible conductive members



23, 1966 E. P. SCHWARTZ ETAL 3,263,632

ROTATIONAL SPEED GOVERNOR WITH A PAIR OF RESILIENT FLEXIBLE CONDUCTIVE MEMBERS Filed Dec. 15, 1961 INVENTORS EUGENE P SCHWARTZ JACK C. HOHNE,JR.

ATTORNEY United States Patent 3,268,682 ROTATIONAL SPEED GOVERNOR WITH A PAIR OF RESILIENT FLEXIBLE CONDUCTIVE MEM- BERS Eugene P. Schwartz, Dayton, and Jack C. Hohne, Jr., Tipp City, Ohio, assignors to Globe Industries, Inc., Dayton, Ohio, a corporation of Ohio Filed Dec. 15, 1961, Ser. No. 160,424 8 Claims. (Cl. 200-80) This invention relates to a rotational speed governor, and is more particularly concerned with a speed governor for miniature electric motors.

Many such high-speed small or miniature motors are used in present-day missiles and other military environments wherein it is of utmost desirability that the speed of such motors be maintained constant. One such governor is illustrated in US. Patent No. 2,846,541, issued August 5, 1958. Such motors are subjected to wide temperature ranges, speed ranges and also to high vibration.

One object of the invention is to provide a speed governor for miniature motors which is capable of maintaining the speed of the motor substantially constant over a Wide speed range and while the motor is subjected to vibration.

Another object of the invention is to provide a rotational speed governor for miniature motors, which is capable of governing at relatively low speeds.

A still further object of the invention is to provide a rotational speed governor which is readily adjustable and which maintains the contacts in alignment throughout the adjustment range.

A further object of the invention is to provide a rotational speed governor for miniature motors which is simply constructed yet sturdily built.

Further objects and advantages of the invention will become more readily apparent upon a reading of the description following hereinafter and upon an examination of the drawings, in which:

FIGURE 1 is a perspective view, partially exploded, of a preferred embodiment of the invention;

FIGURE 2 is a side View, partially in cross-section, of the governor of FIGURE 1;

FIGURE 3 is a rear view of the governor of FIGURE 1; and

FIGURE 4 is a front view of the governor of the invention indicating a modification for extremely low speed operation.

In centrifugal mechanical speed governors, of the type with which the invention is concerned, we have found that by increasing the mass of such centrifugal device at the same angular velocity, a greater centrifugal force is created. At extremely lowspeeds, governors of the type disclosed in the prior art would not have sufi icient mass to open. .T he governor of the invention employs weighted reeds, or reeds with masses thereon, which create additional forces at low speeds to enable the separation of the contacts. At such low speeds the weight of the contact buttons alone is generally insufficient to cause separation of the reeds. Additionally, the added weights of the invention also provide better properties under vibration, since intermittent uncontrolled bouncing of the contacts is prevented and the contacts are held together more tightly. The use of weighted reeds also accomplishes an increase in the resonant point of the springrnass system, and thus avoids many problems which would occur should the reeds vibrate at resonance. The go-vernor of the invention also prov-ides several adjustment points which maintain contact alignment, since both contacts are adjusted simultaneously when changing from one speed control value to another. Better governing characteristics are thereby also obtained.

Referring now to the drawings, a rotational speed govern-or 1 comprises four plate-like segments or sectors 2, 4, 6 and 8, made of conductive material such as beryllium copper. These sectors are electrically separated by nonconductive plastic material 10, such as dialth-ialate. This material is relatively unaffected by heat and/or moisture, and is so molded as to form a sleeve of insulating material 1-1. The segments 2, 4, 6 and 8 are formed from a unitary material which, as indicated in FIGURES 2 and 3, is so slitted as at 13 and 14 as to form a pair of semicircular segments 16 and 1 8 which are electrically separated. The sleeve 11 may extend actually slightly beyond the segments 16 and 18, as indicated in FIGURE 2 at 19. This is for the purpose of ensuring no electrical contact between the motor frame and the governor body. The segments 16 and 18 are thus electrically insulated one from the other. The external sleeve portion 21 of the two segments 16 and 18 essentially forms a commutator-like means which is adapted to be engaged by a pair of suitable brushes 23 and 25', indicated in phantom in FIGURE 2.

The governor is adapted to be mounted upon a shaft 27 of a motor by means of snap ring 29 and adapter plate 31. The adapter plate has a flatted surface 33 on its external circumference to mate with the fiatted surface 20 of the insulating material 10 (see FIGURE 1), while it internally is provided with two fiat surfaces 35 and 37 to engage complementary flat surfaces upon the shaft 27.

Due to the fact that the material 10' is molded into position, the various segments and sleeves of the governor body are retained in rigid assembly. The governor thus withstands centrifugal forces without relative movement between the segments 16, 18, and 2, 4, 6, 8. The separate segments 2 and 8 are integral with the segmental sleeve 16, whereas the segments 4 and 6 are integral with the segmental sleeve 18. Protruding from the segment 8 is a mounting post 12 upon which one governor-reed means is mounted. A similar governor-reed means is mounted upon the post 14, which is integral with the segmental sleeve 18. Only one of the contact means will be described in detail hereinafter, it being readily understood that the other means is similarly constructed. Thus, the reed assembly 36 is attached to the mounting post or conductor stud 12, by means of the screw 54, which is threaded into the threaded hole 60 in the stud 12. This reed assembly comprises the main reed 24 which is provided with two holes 32 and 58 at the ends thereof; and a secondary reed 26 which is provided with the single hole 56 at one end thereof. The two-reed construction is provided in order to enable a speed range for the governor. Thus, in order to obtain operation at higher speeds, both reeds would be employed. One end 38 of the reed 24 is fitted against the squared surface 39 of a weight or block 40, whereas the squared end surface 41 of the reed 2-6 is fitted against the squared surface 43 of the weight 40. A square-headed rive-t 22 having a projecting shank 30 passes through the hole 32 in the reed 24 which is then pressed into a hole 34 in the weight to retain in assembly the reeds 24 and 26. If desired, a bonding adhesive may be placed over the square-headed rivet and reed assembly in order to retain it in place against accidental release upon s'evere vibration. The screw 54 passes through a squared spacer member 52 and through the holes 56 and 58 into the threaded hole 69. The weighted member 40 is so shaped as to provide a surface 44 upon which the contact button 42 is mounted. The contact but-ton 42 is pressed into a hole 45 in the weight 40. Mounted into a threaded hole 51 is an adjustment screw which may preferably be provided with a rounded end to bear against the reeds for adjustment purposes. Thus, upon advancing the screw 50 inwardly, the reeds will be placed under greater tensioning and will require greater forces to spread the contacts apart. This is done for operation at higher speeds. The resilient means or flexible fingers 2-4 and 26 are made of any suitable flexible conductive mate-rial, and preferably one which will not assume a permanent set over the range of tensions applied, and also one which will not fatigue due to the repeated stress cycles through which the reeds must pass.

Once the adjustments of the screws 50 and 70 are made, they may also be fixed in position by the use of a cement or adhesive. These adjusting screws 50 and 70 would preferably be moved an equal amount so that the contacts 42 and 72 would remain in the same relative contacting position when adjusting from a lower speed range to a higher speed range.

When itis desired to operate at a still lower speed range than that accomplished by the embodiment of FIGURES 1-3, the embodiment of FIGURE 4 may be employed. In the embodiment of FIGURE 4, the identical parts are given identical reference numerals as shown in FIGURES 13. Thus, the governor 111 of FIGURE 4 is provided with the sectors 2, 4, 6 and 8, and also is provided with the governor-reed assemblies 36 and 66 mounted upon the conductor studs 12 and 67. However, only a single reed 6'8 and 74 is employed in each of the governor reed assemblies 36 and 66, respectively. The reed 68 is mounted to the block 12 by the screw 54 and is positioned between a pair of spacer members 52 and 76. Similarly the reed 74 is mounted to the conduc tor stud or block 67 by a screw 78 and is held between the spacer members 80 and 82. The reeds 74 and 68 are thus spaced a further distance from the mounting studs than are the reeds in the modification of FIGURE 1. This spacing further apart of the reeds and the employing of reeds which may be of greater thickness than either of the reeds 24 or 26, provides for a lower spring force holding the contacts 72 and 42 together, to enable the separation of the contacts by a smaller centrifugal force. The spacers 76 and 82 may be of any desired thickness to space the reeds any desired additional distance apart to result in the lower speed range. This construction was found extremely desirable in providing a unitary interchangeable governor body for use at various speed ranges. As indicated in FIGURE 4, the stud 67 is slightly-different in configuration from the stud 14 of FIGURE 1, and hence of a larger mass. This was found desirable in order to aid in the balancing of the governor and prevent the necessity of a multiplicity of holes being drilled in the circumference thereof to obtain dynamic balancing of the unit.

By employing various thicknesses of reed material, the speed range can be increased greatly, due to the employment of the weighted reed construction of the invention. From the above description, it is apparent that the segments 16 and 18 and the segments 2, 8 and 4, 6, respectively, of the governor serve as conductor means between the brushes 23 and 25, the conductor reeds or fingers 24 and 26, and the contactor buttons 42 and 72. Due to the fact that the insulating material fills the spaces be-. tween the segments, and the fact that the slot 14 electrically separates the segments 16 and 18, there is direct electrical current connection between the segments 16 and 18 only when the contacts 42 and 72 are in engagement.

When the motor is operating at increasing speed, the centrifugal forces associated with the elements rotating with the shaft 27 increase. As the motor reaches a speed above a desired predetermined speed, the force will become great enough to cause a separation of the contacts 42 and 72; which (when connected into an appropriate electrical circuit conducting power to the motor) will cause power to be removed from the motor, thus tending to decrease the speed. This action occurs rather quickly so that a dithering of the contactsoccurs about the desired speed at which the motor is to run'and the frequency of such dithering is determined by either fluctuations in power supply or in the load to which the motor is subjected.

Although several preferred embodiments of the invention have been described, it will be readily understood that various changes may be made in form, details and proportionate arrangement of parts while still coming within the spirit and scope of the invention as set forth in the appended claims.

We claim:

1. A rotational speed governor comprising a rotatable body including a pair of electric conductor segments electrically separated one from the other, said segments each being provided with electrically conductive protruding studs both located on the same side of a diametral plane, and a pair of resilient flexible conductive means provided with contact elements located on the opposite side of the aforesaid diametral plane and being mounted one on each of said studs, said means being each further provided with a weight member in addition to the contact elements for increasing the mass of the flexible conductive means,

said weight members being each mounted astride and substantially coextensive with the flexible conductive means and extending substantially only slightly beyond said means at one extremity.

2. The governor of claim 1 wherein the contact elements are mounted upon said weight members, said pair of flexible conductive means being so oriented as to extend towards one another and to place the contact elements into spring-loaded engagement one with the other.

3. A rotational speed governor comprising a rotatable body including a pair of electric conductor segments electrically separated one from the other, said segments each being provided with electrically conductive protruding studs, and a pair of resilient flexible conductive elongated reed elements mounted at one end, one on each of said studs, weight members mounted one on the opposite end of each of said reeds, said weight members extending substantially the full length of said reeds towards said studs and being positioned astride said reeds, the weight members extending substantially only slightly beyond said op posite ends of the reeds, and contact element-s mounted upon said weight members, said pair of flexible conductive reed elements being so oriented as to extend towards one another so as to place the contact elements into spring loaded engagement one with the other.

4. The governor of claim 3 wherein a second pair of reed elements are mounted coextensive with the first pair of reed elements.

5. The governor of claim 4 wherein said weight members are provided with stepped surfaces facing said feed elements, and the ends of said reed elements opposite to. their stud mounted ends are bottomed against individual steps of said weight member stepped surfaces.

6. The governor of claim 3 including reed tensioning means mounted upon each of said weight members and cooperating with said reed elements to tension same.

7. A rotational speed governor comprising a rotatable body including a pair of electric conductor segments electrically separated one from the other, said segments each being provided with electrically conductive protruding studs both located on the same side of a diametral plane, a pair of resilient flexible conductive means provided with contact elements, said means being each provided with a Weight member mounted astride and substantially coextensive therewith and extending only slightly beyond said means at the extremity extending on the opposite side of the aforesaid diametral plane to said studs, said contact elements being located on the opposite side of the aforesaid diametral plane to said studs and being mounted one to each of said resilient means, said studs being of dissimilar configuration and dissimilar mass whereby the dynamic balancing of said governor is facilitated by permitting removal of a portion of the stud of the heavier mass. I

8. The rotational speed governor of claim 7 wherein said resilient flexible conductive means comprise reed elements, said weight members each having reed tensioning means mounted thereon and extending towards and engaging said reed elements to tension same.

References Cited by the Examiner UNITED Chichester 20080 Sherwood 20080 X Caton 20080 Lee 20080 Rowe ZOO-80 BERNARD A. GILHEANY, Primary Examiner.

STATES PATENTS ROBERT K. SCHAEFER, Examiner.

Cloud 200-s0 Whitted 200.40 10 A. M. LESNIAK, H. A. LEWI'ITER,

Howard 20080 Assistant Examiners.

Evans et a1 ZOO-80 

1. A ROTATIONAL SPEED GOVERNOR COMPRISING A ROTATABLE BODY INCLUDING A PAIR OF ELECTRIC CONDUCTOR SEGMENTS ELECTRICALLY SEPARATED ONE FROM THE OTHER, SAID SEGMENTS EACH BEING PROVIDED WITH ELECTRICALLY CONDUCTIVE PROTRUDING STUDS BOTH LOCATED ON THE SAME SIDE OF A DIAMETRAL PLANE, AND A PAIR OF RESILIENT FLEXIBLE CONDUCTIVE MEANS PROVIDED WITH CONTACT ELEMENTS LOCATED ON THE OPPOSITE SIDE OF THE AFORESAID DIAMETRAL PLANE AND BEING MOUNTED ONE ON EACH OF SAID STUDS, SAID MEANS BEING EACH FURTHER PROVIDED WITH A WEIGHT MEMBER IN ADDITION TO THE CONTACT ELEMENTS FOR INCREASING THE MASS OF THE FLEXIBLE CONDUCTIVE MEANS, SAID WEIGHT MEMBERS BEING EACH MOUNTED ASTRIDE AND SUBSTANTIALLY COEXTENSIVE WITH THE FLEXIBLE CONDUCTIVE MEANS AND EXTENDING SUBSTANTIALLY ONLY SLIGHTLY BEYOND SAID MEANS AT ONE EXTREMITY. 